GraphQl Query to list selfManagedUsersQueuedForRolePromotion for admin

What does this MR do and why?

• This MR adds graphql query capability to get MemberApproval objects corresponding to the highest new_access_level, for each user.
• Adds the Scope, Finder, Resolver, Type, QueryType for the above

EE: true Changelog: added

ref: #433175

MR acceptance checklist

Please evaluate this MR against the MR acceptance checklist. It helps you analyze changes to reduce risks in quality, performance, reliability, security, and maintainability.

How to set up and validate locally

1. Navigate to http://localhost:3000/-/graphql-explorer (ensure you have queued pending promotion members)

   1. Query

      {
        selfManagedUsersQueuedForRolePromotion(first:3, after:"eyJ1c2VyX2lkIjoiMyIsIm5ld19hY2Nlc3NfbGV2ZWwiOiIzMCIsImlkIjoiNTkifQ") {
          count
          nodes {
            user {
              id
              username
            }
            newAccessLevel {
              stringValue
            }
          }
          pageInfo {
            hasNextPage
            hasPreviousPage
            startCursor
            endCursor
          }
        }
      }

   2. Validate sample response

      {
        "data": {
          "selfManagedUsersQueuedForRolePromotion": {
            "count": 13
            "nodes": [
              {
                "user": {
                  "id": "gid://gitlab/User/3",
                  "username": "annamae.johns"
                },
                "newAccessLevel": {
                  "stringValue": "DEVELOPER"
                }
              },
              {
                "user": {
                  "id": "gid://gitlab/User/4",
                  "username": "marva_schoen"
                },
                "newAccessLevel": {
                  "stringValue": "DEVELOPER"
                }
              },
              {
                "user": {
                  "id": "gid://gitlab/User/5",
                  "username": "theressa.gislason"
                },
                "newAccessLevel": {
                  "stringValue": "DEVELOPER"
                }
              }
            ],
            "pageInfo": {
              "hasNextPage": true,
              "hasPreviousPage": true,
              "startCursor": "eyJ1c2VyX2lkIjoiMyIsIm5ld19hY2Nlc3NfbGV2ZWwiOiIzMCIsImlkIjoiNDkifQ",
              "endCursor": "eyJ1c2VyX2lkIjoiNSIsIm5ld19hY2Nlc3NfbGV2ZWwiOiIzMCIsImlkIjoiNjEifQ"
            }
          }
        }
      }